All of the robot kits and electronics experiments we make here at Bot-In-a-Box are open-source in nature, so you're free to make them yourself with whatever parts you may have available. That being said, if you're looking for a convenient way to pick up the parts you need for a certain project or robot kit, you've come to the right place!
Here at the Bot-In-a-Box Store, you can pick out the parts you'll need, and get a custom PDF shopping list so you can easily find them on eBay. Simply select the parts you're looking for, whether individually or as part of a kit, and add them to your list.
When you add a kit to your list, all the items from that kit will be added to your shopping list. You'll get a chance to edit your list as you go to the next step.
When you've picked out all the parts you think you'll need, proceed to the final step, and click on the "Save As PDF" button to download your shopping list as a custom PDF.
Your shopping list will contain links to eBay listings for the parts you need. Please see Bot-In-a-Box's Affiliate Link Disclosure for more information regarding these links.
It seems to be rather difficult to find a reasonably-priced Pi Zero W computer board on eBay these days. The eBay link selected when you add one to your shopping list is arguably more expensive than it needs to be (especially for Canadian customers). However, it comes with pre-soldered header pins, and it's even more difficult to find that style of board online.